Many people experience excessive pain around their head, neck, and jaw areas, which may include chronic headaches and migraines. For some, these problems can be traced to an overactive trigeminal nerve system, which can result in intense clenching or teeth grinding, especially at night. An NTI is a device worn on the front upper or lower teeth that keeps the canine and/or molars from contacting each other, thus allowing your jaw to relax and giving you a safe night’s sleep.